Sorby Tool - HSS or Carbon Steel?

[Kevin Weir]

I bought this Sorby scraper 30 years ago. I’d like to re-shape it into a negative rake scraper, but I’m not sure if it is a high speed steel or carbon steel tool. If it’s not HSS, I don’t want to use my CBN wheel and will use my regular grinding wheel to do the job. Any suggestions on how to tell?

 

[Brian Gustin]

Easiest way I know of, grind it a little bit on regular grinding wheel and see how the sparks coming off look - there's readily visible difference between HSS and Carbon Steel, I've found.

 

[Don Wattenhofer]

In 1982 I went to England to start up a carburizing furnace in Coventry for about 3 weeks so I had plenty of time to sight see on week ends and I also found a wood working tool store and bought a Sorby 3/4" bowl gouge which I am sure is HS.

 

[Leo Van Der Loo]

Kevin I have one of those thick scrapers, it is HSS, the grinding of HSS give sparks that are a reddish spark color.

This is what carbon steel sparks look like, shown in this picture, to me the sparks kind of explode coming off the grinding wheel and are a much whiter color, normal carborundum grinding wheel or right angle grinder.

 

[Kevin Weir]

Kevin I have one of those thick scrapers, it is HSS, the grinding of HSS give sparks that are a reddish spark color.

This is what carbon steel sparks look like, shown in this picture, to me the sparks kind of explode coming off the grinding wheel and are a much whiter color, normal carborundum grinding wheel or right angle grinder.

View attachment 50403

Thanks Leo. It’s a big scraper so I have a lot of grinding to do to make it a negative rake.

 

[john lucas]

If you get the Slick Stick from woodturnerswonders and touch your CBN wheels with it you can grind soft metals and it wont hurt the wheel. I've been using it wit success for several years now.

 

[Dennis Cameron]

That's one monster scraper

 

[Kevin Weir]

I’m currently shaping the double bevel. I’ve heard 70 degrees is ideal for a negative rake scraper. Can anyone confirm? Thanks.

 

[Dennis Cameron]

I have heard the same 70 degree!

 

[Neil S]

Easiest way I know of, grind it a little bit on regular grinding wheel and see how the sparks coming off look - there's readily visible difference between HSS and Carbon Steel, I've found.

What is Spark Testing? - A Complete Guide - Engineering Choice

Spark testing is a method of determining the general classification of ferrous materials. It normally entails taking a piece of metal, usually scrap, and

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